<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
    <button>按钮4</button>
    <button>按钮5</button>
</body>
<script>
    let btn=document.querySelectorAll('button');
    for(let i=0;i<btn.length;i++){
        btn[i].onclick=function(){
            for(let i=0;i<btn.length;i++){
                btn[i].style.backgroundColor='';
            }
            this.style.backgroundColor='pink';
        }
    }
</script>
</html>